Some numerical investigations of large scale continental deformation.

Journal article

The theory of plate tectonics cannot adequately account for the deformation of the continents: within the oceanic portions of the plates seismic deformation is seen to occur in belts only a few tens of kilometres wide, but seismic, topographic, gravity and field geology data all indicate that the continents are deforming (and have deformed for most of geological time) in zones that are hundreds to thousands of kilometres wide. Qualitatively, this difference in style of deformation may be attributed to the greater buoyancy and lesser strength of the continental lithosphere, but there has been little attempt to treat the process in a quantitative manner. One approach is to abandon the concept of a rigid plate as far as the deforming continent is concerned, and to regard the continental lithosphere as a continuum of known rheology; in particular it is assumed here that the lithosphere is governed, on the million-year timescale and hundred-kilometre length scale, by a non-Newtonian rhelogy which may be approximated by power-law creep. The deformation of such a medium may be investigated numerically, and it is found that this model provides reasonable quantitative agreement between theory and observation as to crustal thickness distribution and relative motions in the India-Asia collision zone, provided that the model lithosphere does not behave as a Newtonian fluid, and provided that it is capable of supporting deviatoric stresses of at least 100-300 bars. -from Author

Authors: England, P

• Publisher: Academic Press
• Journal: Mountain building processes
• Pages: 129-139
• Publication date: 1983-01-01
• Language: English